Configuration manual Reader
12
Modifications, misprints and errors excepted.
English
2.
Description of the configuration parameters
2.4.2.
“InitialQ”
2.4.3.
“Session”
Characteristics:
available from firmware:
v1.30.00
Data type:
Byte (8-bit)
Unit:
–
Value range:
0-3
Description:
Tags to EPCGlobal Class 1 Gen 2 support four different “sessions”. At each session a tag can be given an inventoried
flag to indicate whether or not it has already been detected by the reader during an inventory process. Inventoried
flags have different properties for the individual sessions, which allows recognition of their persistence times.
The time thus indicates how long a tag indicates that it has been detected or not by the reader.
Tag has energy
Tag has no energy
Session 0
unlimited persistence
no persistence
Session 1
persistence greater than 500 milliseconds
but less than 5 seconds
persistence greater than 500 milliseconds but less than
5 seconds
Session 2
unlimited persistence
persistence greater than 2 seconds
Session 3
unlimited persistence
persistence greater than 2 seconds
This configuration parameter instructs the reader the session with which it should work.
Characteristics:
available from firmware:
v1.30.00
Data type:
Byte (8-bit)
Unit:
–
Value range:
0-15
Description:
The value Q in the inventory process specifies how many tags there are in the reader antenna field and which must
be detected. The number x on tag is calculated by the following formula:
The value
Q
is communicated to the tags by the reader, whereupon each of these selects from
x
a random
“Communications slot” for its response. In order to perform an inventory as quickly and efficiently as possible, as
many of the
x
communications slots should be occupied by tags, but without there being any multiple occupation
of communications slots (which would lead to collisions). If the reader detects that the value chosen for
Q
is
too large (hardly any communications slots are occupied) or too small (collisions occur), it will be adjusted
automatically and loaded to the tags. Since this adjustment takes time, the reader with this configuration parameter
should be informed of the approximate number of tags to expect in the antenna field. This allows the number
of communications slots to be set to an appropriate value right from the start of the inventory process.
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